Android ViewPager，ListFragments以及更新列表中的元素时更新

Question

我正在编写我的第一个android应用程序作为大学课程。到目前为止，我有大部分工作，但我遇到了一个问题。

该应用程序是结构化的，所以我有一个活动，设置一个包含3个碎片的ViewPager。每个Fragment都是ListFragment的扩展，列表中填充了从数据库中提取的数据。适配器显示每个ListItem的自定义视图，其中包含一个复选框。

我想要发生的是当复选框是故障单时，所有三个片段都会更新。也就是说，为每个片段重新查询数据库，并更新列表视图。

HomeActivity。这将设置ViewPager。它添加了片段并设置了Fragment Adapter。公共类HomeActivity扩展了SherlockFragmentActivity {

    private FragmentAdapter mPagerAdapter;
    private ViewPager mViewPager;

    /**
    * Set up the view. Add the Fragments to the viewPager, set up tabs. 
    */
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        getSupportActionBar();

        ...

        //Set up Fragments. 
        List<MemoFragment> fragments = new Vector<MemoFragment>();
        fragments.add(new IncompleteMemoFragment());
        fragments.add(new CompleteMemoFragment());
        fragments.add(new UrgentMemoFragment());

        mPagerAdapter = new FragmentAdapter(getSupportFragmentManager(), fragments);

        mViewPager = (ViewPager) findViewById(R.id.viewPager);
        mViewPager.setAdapter(mPagerAdapter);
        mViewPager.setOnPageChangeListener(new TabListener(mTabHost,mViewPager));
        mViewPager.setOffscreenPageLimit(3);
    }
    ...
}

片段适配器

public class FragmentAdapter extends FragmentPagerAdapter {

    private List<MemoFragment> mFragments;

    public FragmentAdapter(FragmentManager fm, List<MemoFragment> fragments) {
        super(fm);
        this.mFragments = fragments;
    }

    @Override
    public MemoFragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return this.mFragments.size();
    }

}

MemoFragment类，IncompleteMemoFragment，CompleteMemoFragment，UrgentMemoFragment都扩展了它，并且99％相同，它们只是从数据库中提取一组不同的数据。

public class MemoFragment extends SherlockListFragment {

    protected DatabaseSource datasource;

    /**
     * Creates the View. 
     */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_memo_list, container, false);

        datasource = new DatabaseSource(container.getContext());
        datasource.open();

        List<Memo> values = getMemos();

        datasource.close();

        MemoListViewAdaptor adapter = new MemoListViewAdaptor(container.getContext(), values);

        setListAdapter(adapter);

        return rootView;
    }

    /**
    * Gets the memos to show.
    * @return the memos to show.
    */
    public List<Memo> getMemos(){
        return datasource.getAllMemos();
    }

}

这是MemoListViewAdapter。在这里，您将看到我试图查找更改的复选框。

public class MemoListViewAdaptor extends ArrayAdapter<Memo> {
    private final Context mContext;
    private final List<Memo> mMemos;

    /**
     * Save the context and the Memos
     * @param context the context to save
     * @param memos the memos to save.
     */
    public MemoListViewAdaptor(Context context, List<Memo> memos) {
        super(context, R.layout.memo_list_row, memos);
        this.mContext = context;
        this.mMemos = memos;
    }

    /**
     * Get the view. Sets up the list to use the custom view. 
     */
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View rowView = inflater.inflate(R.layout.memo_list_row, parent, false);

        ...
        CheckBox done = (CheckBox) rowView.findViewById(R.id.done);

        Memo memo = mMemos.get(position);


        done.setOnClickListener(new ClickListener(memo));
        if(memo.getCompleteness() == Memo.COMPLETE){
            done.setChecked(true);
        }

        ...

        return rowView;
    }

}

而且，最后这里是Click监听器。

public class ClickListener implements OnClickListener {
    private Memo memo;

    ClickListener(Memo memo){
        this.memo = memo;
    }
    @Override
    public void onClick(View v) {
        if(v.getClass() == CheckBox.class){
            Log.v("com.milner.memolist", "These people are crazy. This task is done");
            if(((CheckBox)v).isChecked()){
                memo.setCompleteness(1);
            }else{
                memo.setCompleteness(0);
            }
            DatabaseSource datasource = new DatabaseSource(v.getContext());
            datasource.open();
            datasource.updateMemo(memo);
            datasource.close();

        }else{
        ...
        }
    }  
}

所以你有它。多数民众赞成我到目前为止！正如你所看到的，我可能是一个非常复杂的方式...我没有太多的android经验。我想我真正想做的是在勾选复选框时重新加载所有片段。

是否有捷径可寻？有没有复杂的方法来做到这一点？我只是无法理解最后一点！

希望你能帮忙！ :)

谢谢

汤姆M.